Kolkata:  Kolkata witnessed an unprecedented pitched battle between the BJP workers and the police today as the party attempted to hold a rally to Lalbazar, the state police headquarters in the heart of the city. Following the violence, during which the police used batons, tear gas and water cannons and the party retaliated with stones, Governor Kesari Nath Tripathi stepped in and called for an all-party meeting tomorrow. The ruling Trinamool Congress said it would attend the meeting as the Governor "is a constitutional body".